Device for Mixing Two Gaseous Components and Burner in Which This Device Is Employed

1. Field of the Invention

The invention is based on a device for mixing two gaseous components in accordance with the preamble to claim 1 and of a burner in accordance with the preamble to claim 7.

2. Discussion of the Background

A burner with two partial conical bodies is known from the patent specification EP 0 321 809. This burner has two tangentially directed inlet flow gaps for air. Liquid fuel is admixed with the air in the region of the inlet flow gaps by means of inlet flow nozzles. This burner does not have an optimum configuration for the admixture of gaseous fuels.

Accordingly, one object of this invention is to provide aid in this respect. The invention, as specified in the independent claims, achieves the object of creating a device for mixing two gaseous components, the device leading to particularly intimate and uniform mixing, and of providing a burner whose ability to generate a primary temperature distribution which is as even as possible is advantageously increased by this device.

The advantages achieved by the invention may be seen essentially in the fact that particularly rapid mixing of the two components can be achieved by simple measures in the region of the supply flow of one of the gaseous components. If this device is employed in a burner of the type described, particularly uniform mixing of the combustion air with the gaseous fuel is achieved before initiation of the reaction and the result of this is a very good combustion characteristic, the appearance of undesirable combustion products such as NO.sub.x being, in particular, advantageously reduced. Furthermore, the fuel is better utilized so that the occurrence of unsaturated hydrocarbon compounds and carbon monoxide is suppressed.

The further embodiments of the invention are the object matter of the dependent claims.

A more complete appreciation of the invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings (which only represent one possible embodiment path) wherein:

FIG. 1 shows a first embodiment of the invention

FIG. 2 shows a diagrammatic partial section through the arrangement of FIG. 1

FIG. 3 shows a further diagrammatic partial section.

Referring now to the drawings, wherein like reference numerals and letters designate identical or corresponding parts throughout the several views, FIG. 1 shows one of the burners 1 of a gas turbine installation in a diagrammatic, very simplified, perspective view. This burner 1 can also be employed in other installations in which hot gases are generated. The burner 1 consists of two hollow partial conical bodies 2, 3 whose parallel central axes are offset relative to one another in a radial direction. At the end of the burner, a collar 4, which is only partially shown, connects the partial conical bodies 2, 3 together. The other holding devices for the burner 1, and also the supply flow ducts for the combustion air, are not shown for ease of understanding. Because of the offset between the partial conical bodies 2, 3, two inlet flow gaps 5 respectively occur between an outer edge 6 and an inner edge 7 adjacent to it of the partial conical bodies 2, 3. The two partial conical bodies 2, 3, respectively, have the see included angle. In the region of the apexes of the partial conical bodies 2, 3, there is a burner nozzle 8, indicated by an arrow 9 which shows the supply of liquid fuel to the burner nozzle 8. The burner 1 can also be operated, however, without feeding the burner nozzle 8.

A guide plate 10 is joined, usually rigidly, to each of the outer edges 6. It is, however, also conceivable for this guide plate 10 to be adjustably attached. An inlet flow duct 11, which opens into the inlet flow gap 5, is formed between each guide plate 10 and the opposite outer wall of the corresponding partial conical body 2 or 3. The path of the inlet flow duct 11 is shown diagrammatically in FIG. 2. Arrows 12 indicate the inlet flow of the combustion air, which flows almost tangentially through the inlet flow gap 5 into the inside of the partial conical body 2, 3. The rest of the combustion air supply system is not shown. Inlet flow nozzles 13 are provided along the outer edge 6 for introducing gaseous fuel or fuel prepared in gaseous form into the region of the inlet flow gap 5. The associated fuel supply duct, which is located at the outside on the burner 1, is not shown in FIG. 1 for ease of understanding but the fuel supply duct 14 is shown in FIG. 2. An arrow 15 gives the flow direction of the entering gaseous fuel in FIG. 2.

As may also be seen in FIG. 1 and 2, ramps 16 are attached to the guide plates 10 in the inlet flow duct 11. The ramps become thicker in the direction of the combustion air flowing into the inlet flow gap 5 and end with a separation edge 17 in front of the inlet flow gap 5. The inlet flow nozzles 13 are located in the region near and/or after the separation edge 17 of the ramps 16. The inlet flow nozzles 13 are located in the region between one and approximately five times the hydraulic diameter of the ramps 16. In addition, the distance between the inlet flow nozzles 13 and the separation edge 17 is relatively large compared with the diameter of the inlet flow nozzles 13. The eddying flow of the combustion air separating from the separation edge 17 is shown by an arrow 18 in FIG. 2. The ramps 16 extend into the inlet flow duct 11 over a length which corresponds approximately to between three and five times the height of the inlet flow gap 5. The same dimension is also the minimum length of the inlet flow duct 11 but an extension of the inlet flow duct 11 beyond this minimum dimension can introduce a flow improvement.

In FIG. 1, only two ramps 16 are provided on each of the guide plates 10. It is, however, advantageous to provide the whole length of the guide plates 10 with such ramps 16 in order to achieve good mixing between the gaseous fuel and the entering combustion air in the narrower part of the burner also. It is also possible to provide only part of the burner 1--the part adjacent to the outlet into the combustion chamber--with ramps 16 because particularly good mixing between the gaseous fuel and the combustion air is important in this region.

The section III--III of FIG. 2 is shown in FIG. 3. An intermediate space 19 is respectively provided between the ramps 16 and is of approximately the same width as the ramps. Fuel jets 20 indicate the region behind the section plane in which the inlet flow nozzles 13 introduce the gaseous fuel. Diagrammatically sketched vortices 21 show the points where the entering combustion air eddies most strongly. The vortices generated by the ramps 16 are intended to reinforce the momentum of the fuel jets 20. For this reason, the inlet flow nozzles 13 for the fuel inlet are arranged in such a way that the fuel reaches the region of the maximum air velocity components directed radially inwards in the region of the vortex 21. The width of the intermediate spaces 19 does not have to correspond to the width of the ramps 16 in all applications. The optimum mixing conditions can be adjusted from case to case when the burner is optimized for particular uses. It is, therefore, also possible to configure burners in such a way that the width of the ramps 16 increases in the burner outlet direction.

The mixing can also be influenced by the height of the separation edge 17. In general, the separation edge has a height between approximately 25% and approximately 50% of the height of the inlet flow gap 5. These figures can also be optimized to suit the particular use of the burner. The ramps 16 can also, however, be replaced or supplemented by similarly acting milled recesses in the guide plate 10 and this variant could be advantageously selected, particularly to improve existing installations.

It is not just for the mixing of two gaseous components in burners or similar devices, as described in the embodiment example, that the device according to the invention can be advantageously employed. It can also be employed wherever a particularly intimate mixing of two gases is demanded. The intimate mixing of different vapors, or even vapors and gases, is also conceivable by means of this device.

FIGS. 1 to 3 are considered in somewhat more detail in order to explain the mode of operation. The gaseous fuel entering through the inlet flow nozzles 13 is mixed with the combustion air. The momentum of the jets of the high calorific value fuel entering is not sufficient for intimate mixing between the two components, nor is it possible to increase this momentum with reasonable technical outlay. The ramps 16, with the separation edge 17, in the inlet flow duct 11 generate a specific arrangement of longitudinal vortices in the inlet flow gap 5, as is indicated by the arrow 18 and the vortex 21. These longitudinal vortices meet the fuel jets 20, entrain the gaseous fuel and ensure optimum mixing of the fuel with the combustion air. The actual combustion takes place in the known flame front 22 of this type of burner. A reverse flow zone 23 also forms and this stabilizes the flame front 22. The intimate mixing of the fuels with the combustion air in this burner leads to combustion with very little thermal generation of NO.sub.x and good utilization of the energy content of the fuels.

Obviously, numerous modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein.